<template>
  <view>
    <view class="scroll-view-container">
      <!-- 左侧的滑动 -->
       <scroll-view class="left-scroll-view" scroll-y="true"  :style="{height:wh+'px'}">
        <block v-for="(item,i) in cateList":key="i">
          <view :class="['left-scroll-view-item',i===active ? 'active' :'']" @click="activeChanged(i)">{{item.cat_name}}</view>
        </block>
       </scroll-view>
      <!-- 右侧的滑动 -->
      <scroll-view scroll-y="true"  :style="{height:wh+'px'}" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
          <!-- 二级分类的标题 -->
          <view class="cate-lv2-title">
            /{{item2.cat_name}}/
          </view>
          <!-- 当前二级分类下的三级分类列表 -->
          <view class="cate-lv3-list">
            <!-- 三级分类的item项 -->
            <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodList(item3)">
              <!-- 三级分类的图片 -->
              <image :src="item3.cat_icon" ></image>
              <!-- 三级分类的文本 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        // 当前设备可用的高度
        wh:0,
        cateList:[],
        active:0,
        //2级分类的列表
        cateLevel2:[],
        scrollTop:0
      };
    },
    onLoad() {
     const sysInfo= uni.getSystemInfoSync()
     console.log(sysInfo)
     this.wh=sysInfo.windowHeight
     this.getCateList()
    },
    methods:{
      //获取分类列表的数据
     async getCateList(){
     const{data:res} =await  uni.$http.get('/api/public/v1/categories')
     if(res.meta.status!==200) return uni.$showMsg()
       this.cateList=res.message
       //为二级分类复制
    this.cateLevel2= res.message[0].children
      },
      activeChanged(i){
        this.active=i
        //重新为二级父类复制
      this.cateLevel2=  this.cateList[i].children
      this.scrollTop=this.scrollTop===0?1:0
      },
      //跳转到商品列表页面
      gotoGoodList(item){
        uni.navigateTo({
          url:'/subpkg/goods_list/goods_list?cid='+item.cat_id
        })
      }
    }
  }
</script>

<style lang="scss">
.scroll-view-container{
  display: flex;
  .left-scroll-view{
    width: 120px;
    .left-scroll-view-item{
      background-color: #F7F7F7;
      line-height: 60px;
      text-align: center;
      font-size: 12px;
      &.active{
        position: relative;
        background-color: #FFFFFF;
        &::before{
          content: '';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #C00000;
          position: absolute;
          top: 50%;
          left: 0;
          transform: translateY(-50%);
        }
      }
    }
  }
}
.cate-lv2-title{
  font-size: 12px;
  font-weight: bold;
  text-align: center;
  padding: 15px 0;
}
.cate-lv3-list{
  display: flex;
  flex-wrap: wrap;
  .cate-lv3-item{
    width: 33.33%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-bottom: 10px;
    image{
      width: 60px;
      height: 60px;
    }
    text{
      font-size: 12px;
    }
  }
}
</style>
